IA-32 architecture
3DNow! opcodes




The PREFETCHx instruction is using the reg field of the mod R/M byte to determine the desired prefetch type (x).

 
0Fh xxh
 
xDh xEh xFh
 
0xh
 
PREFETCHx
M
FEMMS refer to
table
below
 
opcode PREFETCHx instruction
0Fh,0Dh,xx000xxxb PREFETCH line into E state
0Fh,0Dh,xx001xxxb PREFETCHW line into M state
0Fh,0Dh,xx002xxxb reserved, alias to PREFETCH
0Fh,0Dh,xx003xxxb reserved, alias to PREFETCH
0Fh,0Dh,xx004xxxb reserved, alias to PREFETCH
0Fh,0Dh,xx005xxxb reserved, alias to PREFETCH
0Fh,0Dh,xx006xxxb reserved, alias to PREFETCH
0Fh,0Dh,xx007xxxb reserved, alias to PREFETCH



The 3DNow! instruction encoding differs from the regular instruction encoding, in that the mod R/M (and SIB) byte as well as an optional displacement follow directly after the two 0Fh prefix bytes. The byte selecting the instruction itself is appended as the last byte.



0Fh 0Fh
... xxh
 
x0h
 
x1h x2h x3h x4h x5h x6h x7h
 
0xh
 
 
1xh
 
 
2xh
 
 
3xh
 
 
4xh
 
 
5xh
 
 
6xh
 
 
7xh
 
 
8xh
 
 
9xh
 
PFCMPGE
Pq,Qq
PFMIN
Pq,Qq
PFRCP
Pq,Qq
PFRSQRT
Pq,Qq
 
Axh
 
PFCMPGT
Pq,Qq
PFMAX
Pq,Qq
PFRCPIT1
Pq,Qq
PFRSQIT1
Pq,Qq
 
Bxh
 
PFCMPEQ
Pq,Qq
PFMUL
Pq,Qq
PFRCPIT2
Pq,Qq
PMULHRW
Pq,Qq
 
Cxh
 
 
Dxh
 
 
Exh
 
 
Fxh
 

0Fh 0Fh
... xxh
 
x8h
 
x9h xAh xBh xCh xDh xEh xFh
 
0xh
 
PI2FW*
Pq,Qq
PI2FD
Pq,Qq
 
1xh
 
PF2IW*
Pq,Qq
PF2ID
Pq,Qq
 
2xh
 
 
3xh
 
 
4xh
 
 
5xh
 
 
6xh
 
 
7xh
 
 
8xh
 
PFNACC*
Pq,Qq
PFPNACC*
Pq,Qq
 
9xh
 
PFSUB
Pq,Qq
PFADD
Pq,Qq
 
Axh
 
PFSUBR
Pq,Qq
PFACC
Pq,Qq
 
Bxh
 
PSWAPD*
Pq,Qq
PAVGUSB
Pq,Qq
 
Cxh
 
 
Dxh
 
 
Exh
 
 
Fxh
 



note: The opcodes marked with * are enhanced 3DNow! opcodes.



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